Today, there is no industrial life nor normal life without energy, the use of energy is therefore one of the clearest indicators of the degree of development of a country.
The most industrialized nations that are the largest consumers of electricity continue to rely on energy as a driver of growth and economic development. The energy sector plays an important and special role in every economy.
And with the issue of climate change and its impact, is now well known and unprecedented mobilization in any society. The energy transition on the three pillars is decarbonization, decentralization, and numeration. These are the main drivers of the return to clean technology and the emergence of a new green economy.
Renewable energies, which have long been overshadowed by fossil fuels as energy supply, have been at the forefront since the resurgence of concerns about global warming and the recent rise in oil prices. Renewable energies have also entered a virtuous circle of technological progress and cost reduction, making them increasingly competitive with fossil fuels, which explains, in part, this renewed interest. This suggests, then, major development potential for the coming years.
Renewable resources can be divided into two categories:
- Sources available in unlimited quantities: solar, water, wind, geothermal, etc.
- biomass sources, which can be divided according to their origin: energy wood, agricultural biomass, and industrial and household waste.
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Bacteria, a miniature new source of energy
Climate change obliges humans to seek alternatives to fossil fuels as sources of energy and raw materials for chemical production. Many scientists have worked to create artificial photosynthetic systems to generate renewable energies and simple organic chemicals using sunlight. Progress has been made, but the systems are not efficient enough for the commercial production of fuels and raw materials.
Thanks to natural biochemical processes they use to degrade the substances in their environment (sugars, proteins, lipids, carbon dioxide, etc.) in order to make other essential substances for their maintenance and growth (fatty acids, sugars, etc.), some bacteria produce interesting molecules from energy.
The metabolism of some bacteria generates an electrical current or biogas that can supply electricity to many houses.
Some bacteria, such as the soil bacteria Shewanella oneidensis or Geobacter sulfur-duces, can generate electricity via a breathing process. Known as “Exo generators”, these strains naturally emit electrons when they consume the organic substance in the absence of oxygen; it is then enough to collect and channel this flow to directly dispose of electricity.
As for Cyanobacteria, which use photosynthesis like plants, they produce hydrogen. The reaction makes it possible to synthesize organic substances from water (H2O), carbon dioxide (CO2), and solar energy and releases oxygen (O2). Hydrogen is also released transiently at the beginning of photosynthesis. This is the long-awaited fuel needed to power the famous “fuel cells”. Batteries that, if we have enough hydrogen, could make the cars of the future run by rejecting only water for any waste.
To exploit the talents of bacteria chemists, it is also possible to modify their genome to artificially produce the desired energy substance (a fuel for example), from a widespread and universal raw material (waste, CO2, etc.).
How to use it?
The energy source mobilizes bacteria and wastewater to create electricity. The principle is simple and follows the conventional battery process. Some reprocessing plants, for example, use bacteria to convert the organic substances into renewable energy, biogas. It can then be transformed into heat, electricity, and fuel. The interest of this resource is to preserve fossil energy reserves.
And while its production remains modest, it is also not negligible: a medium-sized plant, which processes 30,000 tonnes of waste per year, provides enough electricity to power 14,000 households, excluding heating.
The conventional battery process consists of an anode that releases electrons and a cathode that recovers them. The electron transfer from the negative pole to the positive pole, creating a chemical reaction that transforms into an electric current.
When it comes to renewable energy, we are most often talking about wind turbines, solar collectors, or water power. However, there are other solutions such as energy production from biomass: wood, biofuels, or biogas.
The population in the world is booming, leading to an increased food requirement and the generation of more garbage. Recycling contributes to fighting poverty and environmental sanitation.
Anaerobic digestion or mechanization.
Mechanization is an anaerobic digestion process that generally achieves a dual-energy recovery goal through methane recovery (CH4) and stabilization of organic waste with a view to material recovery by its partial return to the ground.
This biological degradation involves a specialized and diversified microflora that requires specific and adapted bio-physicochemical conditions. Like all biological reactions, the reactions involved in anaerobic degradation are carried out in the presence of water, that is to say in an aqueous medium.
The technique used in anaerobic systems is called anaerobic digestion or mechanization. It is a complex process involving several biological reactions. It is generally described in four main steps, involving four specific microbial consortia interacting with each other. In this way, complex molecules are metabolized to their mineralization, that is, their transformation into methane and CO2. These steps are hydrolysis, acidogenesis, acetogenesis, and methanogenesis.
Biogas technology is based on the recycling concept where organic mass is converted by methane fermentation into simple energy, clean and ready to satisfy many the need for energy in a fully decentralized manner.
The potential for biogas production from local biomass and with a family digester can be a source of sustainable energy but the fact remains that anaerobic fermentation depends on several parameters such as substrate source, temperature, agitation… etc.